IEEE C802.16m-09/1886
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Proposed Changes to Handover MAC Messages (15.2.6.7/15.2.7.2.9.2.3)
Date
Submitted
2009-08-28
Source(s)
Kelvin Chou, Yih-Shen Chen, I-Kang Fu and
Paul Cheng
Kelvin.Chou@mediatek.com
MediaTek Inc.
Re:
Letter Ballot #30 on the Draft Amendment (IEEE P802.16m/D1)
Abstract
This contribution proposes clean up to the MAC messages for handover
Purpose
Propose to be discussed and adopted by TGm for the 802.16m Amendment
Notice
Release
Patent
Policy
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and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name
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<http://standards.ieee.org/board/pat>.
Proposed Changes to Handover MAC Messages (15.2.6.7/15.2.7.2.9.2.3)
Kelvin Chou, Yih-Shen Chen, I-Kang Fu and Paul Cheng
MediaTek Inc.
I. Introduction
P802.16m/D1 has defined so many HO features as follows:
-
Single-carrier HO (15.2.7);
-
EBB HO using HO Reentry Interleaving Interval (15.2.7);
-
EBB HO using multiple carriers (15.2.9.2.9);
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IEEE C802.16m-09/1886
-
HO with secondary carrier pre-assignment (15.2.9.2.9).
Besides, several parameters regarding the above HO features have been defined in the MAC management
message section (15.2.6) and in the Multi-Carrier HO section (15.2.9.2.9.2.3) as follows:
-
HO_Reentry_Mode (15.2.6.9 AAI_HO-CMD)
-
HO Reentry Interleaving Interval (15.2.6.9 AAI_HO-CMD)
-
MCHO Indication (15.2.6.9 AAI_HO-CMD)
-
Multi-Carrier_Support (15.2.9.2.9.2.3.5 AAI_HO-REQ in multi-carrier section)
-
Carrier Preassignment Indication (15.2.9.2.9.2.3.5 AAI_HO-REQ in multi-carrier section)
-
Multi-Carrier Indication (15.2.9.2.9.2.3.6 AAI_HO-CMD in multi-carrier section)
However, current definitions for the above parameters are ambiguous, and how to trigger each HO features
through the above parameters is not clear. This contribution proposes a clarification and summary of the
relationships among these HO features and parameters, which is illustrated in the following table:
HO Reentry Mode
Carrier Preassignment
Indication
0
1
HORII* > 0
HORII* = 0
0 single-carrier HO (15.2.7)
single-carrier EBB HO within
HORIIs (15.2.7)
multi-carrer EBB HO (15.2.9)
single-carrier HO (15.2.7)
with
1
secondary carrier
preassignment (15.2.9)
single-carrier EBB HO within
HORIIs (15.2.7)
with
secondary carrier
preassignment (15.2.9)
multi-carrer EBB HO (15.2.9)
with
secondary carrier
preassignment (15.2.9)
*HORII: HO Reentry Interleaving Interval
Based on the above table, text modification regarding HO MAC messages are proposed in this contribution,
while text modification regarding general HO procedures and MCHO procedures is provided in C802.16m09/1888 or the latest revision thereof.
II. Proposed Text
{Apply the following text modification to P802.16m/D1, Section 15.2.6.7 at page 55, line 3 as follows:}
--------------------------------------------------------- Text Start ---------------------------------------------------------------15.2.6.7 AAI HO-IND
The AMS may send the AAI_HO-IND MAC management message in HO preparation, HO execution and HO
cancellation. The AAI_HO-IND message includes the following information:
HO Event Code: This is used to distinguish AAI_HO-IND among different scenarios:
0b00: Target ABS selection in case of multiple candidate T-ABSs.
0b01: All target ABSs in AAI_HO-CMD are unreachable. In this case, the AMS shall include a new
target ABS that was not included in AAI_HO-CMD.
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IEEE C802.16m-09/1886
0b10: AMS unable to stay connected to serving ABS until expiration of disconnect time
0b11: HO cancel.
For HO Event Code = 0b00, the following parameters shall be included:
Target ABS ID
The specific format of the AAI_HO-IND message is TBD
Table XXX—Parameters for AAI_HO-IND message
Name
HO Event Code
Value
Usage
0b00: Target ABS selection in case of This is used to distinguish
multiple candidate T-ABSs.
AAI_HO-IND among different
scenarios
0b01: All target ABSs in AAI_HO-CMD are
unreachable. In this case, the AMS shall
include a new target ABS that was not
included in AAI_HO-CMD.
0b10: AMS unable to stay connected to
serving ABS until expiration of disconnect
time
0b11: HO cancel.
Target ABS ID
Physical_Carrier_Index
Shall be included when HO Event
Code = 0b00
Physical carrier index of the Target ABS
where an AMS will perform network reentry
procedure
May be included when the target
ABS is a multi-carrier ABS and
HO Event Code = 0b00
15.2.6.8 AAI_HO-REQ
In MS-initiated HO, the AMS shall send the AAI_HO-REQ to S-ABS to initiate the HO procedure. The following parameters shall be included in the AAI_HO-REQ message:
HO type:
Bit #0: HO
Bit #1: Zone switch
Report metric: Bitmap indicator of trigger metrics that the MS reports in this message. The bitmap interpretation
for the metrics shall be:
Bit #0: BS CINR mean
Bit #1: BS RSSI mean
Bit #2: Relative delay
Bits #3-6: Reserved; shall be set to zero.
N_New_BS_Index: Number of neighboring ABSs to be considered for HO, which are included in AAI_NBRADV message.
For each recommended neighbor BS, the following parameters shall be included:
Neighbor_ABS_ID
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IEEE C802.16m-09/1886
According to Report metric that MS indicates, the AAI_HO-REQ message includes the following parameters:
ABS CINR mean
ABS RSSI mean
Relative delay
Table XXX—Parameters for AAI_HO-REQ message
Name
HO Type
Value
Usage
Bit #0: HO
Bit #1: Zone Switch
Report Metric
Bit #0: BS CINR mean
Bitmap indicator of trigger metrics
that the MS reports in this message.
Bit #1: BS RSSI mean
Bit #2: Relative delay
Bits #3-6: Reserved; shall be set to zero.
N_New_BS_Index
Number of neighboring ABSs to be
considered for HO, which are included in
AAI_NBR-ADV message.
Neighbor_ABS_ID
Shall be included for each
recommended neighbor BS
ABS CINR mean
Shall be included if Report Metric
Bit #0 is set to 1
ABS RSSI mean
Shall be included if Report Metric
Bit #1 is set to 1
Relative delay
Shall be included if Report Metric
Bit #2 is set to 1
Multi-Carrier Support
0: the AMS only supports single-carrier
handover procedure defined in 15.2.7 and will
disconnect all its active secondary carriers
before handover
1: the AMS supports the multi-carrier
handover procedure defined in section
15.2.9.2.9.2. No matter the AMS which is
capable of multi-carrier operation is in singlecarrier mode or multi-carrier mode
Carrier Preassignment
Indication
Indicates whether AMS needs pre-assignment
of secondary carriers at the Target ABS.
4
May be included when MultiCarrier Support = 1
IEEE C802.16m-09/1886
15.2.6.9 AAI_HO-CMD
The S-ABS shall send AAI_HO-CMD to initiate the HO procedure, or to acknowledge the AAI_HO-REQ sent
by the AMS. The AAI_HO-CMD message shall include the following parameters:
Mode:
0b00: HO command
0b01: Zone switch command from MZone to LZone
0b11: AMS HO request rejected (ABS in list unavailable).
In case of Mode = 0b00, AAI_HO-CMD message should include one or more target ABS and the following
parameters:
HO_Reentry_Mode: If set to 1, the AMS maintains communication with Serving ABS while performing
network reentry with the Target ABS; otherwise the AMS disconnects from the Serving ABS before performing
network reentry with the Target ABS. The following parameters shall be included when HO_Reentry_Mode is
set to 1:
HO_Reentry_Interleaving Interval: If HO_Reentry_Interleaving Interval is greater than zero, the AMS
continues data transmission with the Serving ABS within the HO_Reentry_Interleaving Interval and
performs network reentry to the target ABS in the remaining time. Otherwise if
HO_Reentry_Interleaving Interval is set to 0, the AMS maintains communication with Serving ABS on
one carrier while performing network reentry with Target ABS on another carrier.
For HO_Reentry_Interleaving_Interval >= 0, the following parameter is further included:
HO_Reentry Iteration: The requested number of iterating HO Reentry Intervals by an
AMS.
Disconnect time offset: Difference between Disconnect time and Action time in units of frames. The value of
disconnect time shall be calculated for each T-ABS by adding/subtracting this value with the value of Action
time specified for this T-ABS. For HO_Reentry_Mode = 0, Disconnect time will be (Action time - Disconnect
time offset); for HO_Reentry_Mode = 1, Disconnect time will be (Action time + Disconnect time offset).
Resource_Retain_Time
For Mode = 0b00 and for each target ABS, the following parameters shall be included:
Target ABS ID
Action Time: Action Time included in this message is the absolute frame number at the serving ABS.
CDMA_RNG_FLAG: The following parameters may be included when CDMA_RNG_FLAG=1:
Dedicated CDMA ranging code/opportunity
HO process optimization: For each Bit location, a value of 0 indicates the associated reentry management
messages shall be required, a value of 1 indicates the reentry management message may be omitted.
Bit #0: Omit AAI_SBC-REQ/RSP management messages during reentry processing
Bit #1: Omit PKM Authentication phase except TEK phase during current reentry processing
Bit #2: Seamless HO
Bit #3: TBD.
Ranging initiation deadline.
Service level prediction, which indicates the level of service the AMS can expect from this ABS. The following
encodings apply:
0 = No service possible for this AMS
1 = Some service is available for one or several service flows authorized for the AMS
2 = For each authorized service flow, a MAC connection can be established with QoS specified by the
AuthorizedQoSParamSet.
3 = No service level prediction available.
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IEEE C802.16m-09/1886
For Mode = 0b00 for each target ABS which is multi-carrier ABS, the following parameters should be included:
Physical_Carrier_Index: Physical carrier index of the Target ABS where AMS will perform network reentry
procedure.
For Mode = 0b00 for an AMS with multi-carrier capability, the following parameters should be included:
MCHO_Indication: If MCHO_Indication is 0, the AMS shall disconnect all its active secondary carriers and
perform single-carrier handover procedure per 15.2.6.3; otherwise it performs multi-carrier handover procedure
per 15.2.9.2.9.2.
In case of Mode = 0b01, the AAI_HO-CMD message is used as a zone switch instruction from MZone to LZone,
and the following parameters shall be included:
HO_Reentry_Mode: If set to 1, the AMS maintains communication with MZone while performing network
reentry with LZone in the same frame or on another carrier; otherwise the AMS disconnects from the MZone
before performing network reentry with the LZone.
Action Time: This value is defined as the frame number that AMS starts zone switch. Action Time included in
this message is indicated by frame number.
Resource_Retain_Time
CDMA_RNG_FLAG: The following parameters may be included when CDMA_RNG_FLAG=1:
Dedicated CDMA ranging code/opportunity
LZone information: LZone information for the AMS to switch from MZone to LZone.
In case of Mode = 0b11, AAI_HO-CMD message shall not include any target ABS.
Table XXX—Parameters for AAI_HO-CMD message
Name
Mode
Value
Usage
0b00: HO command;
0b01: Zone switch command from MZone to
LZone;
0b11: AMS HO request rejected (ABS in list
unavailable). In this case, AAI_HO-CMD
message shall not include any target ABS.
HO Reentry Mode
1: the AMS maintains communication with
Serving ABS while performing network
reentry with the Target ABS (Mode=0b00);
or the AMS maintains communication with
MZone while performing network reentry
with LZone in the same frame or on another
carrier (Mode=0b01).
Should be included when Mode =
0b00.
Shall be included when Mode =
0b01.
0: the AMS disconnects from the Serving
ABS before performing network reentry
with the Target ABS (Mode=0b00); or the
AMS disconnects from the MZone before
performing network reentry with the LZone
(Mode=0b01).
HO Reentry Interleaving
If HO Reentry Interleaving Interval > 0, the
6
Shall be included when HO
IEEE C802.16m-09/1886
Interval
AMS continues data transmission with the
Serving ABS within the HO Reentry
Interleaving Interval and performs network
reentry to the target ABS in the remaining
time.
Reentry Mode is set to 1
If HO Reentry Interleaving Interval =0, the
AMS performs multi-carrier EBB HO
procedure per 15.2.9.2.9.2.2.1
HO Reentry Iteration
The requested number of iterating HO
Reentry Intervals by an AMS.
Shall be included when HO
Reentry Interleaving Interval > 0
Disconnect time offset
Difference between Disconnect time and
Action time in units of frames. The value of
disconnect time shall be calculated for each
T-ABS by adding/ subtracting this value
with the value of Action time specified for
this T-ABS.
Should be included when Mode =
0b00.
For HO_Reentry_Mode = 0, Disconnect
time will be (Action time - Disconnect time
offset);
For HO_Reentry_Mode = 1, Disconnect
time will be (Action time + Disconnect time
offset).
Resource_Retain_Time
Should be included when Mode =
0b00.
Shall be included when Mode =
0b01.
Target ABS ID
Action Time
Shall be included for each target
ABS when Mode=0b00
(Mode=0b00) Action Time included in this Shall be included for each target
message is the absolute frame number at the ABS when Mode=0b00.
serving ABS
Shall be included when Mode =
(Mode=0b01) This value is defined as the 0b01.
frame number that AMS starts zone switch.
Action Time included in this message is
indicated by frame number
CDMA_RNG_FLAG
Shall be included for each target
ABS when Mode=0b00.
Shall be included when Mode =
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IEEE C802.16m-09/1886
0b01.
Dedicated CDMA ranging
code/opportunity
HO process optimization
May be included when
CDMA_RNG_FLAG=1
For each bit location, a value of 0 indicates
Shall be included for each target
the associated reentry management messages ABS when Mode=0b00
shall be required, a value of 1 indicates the
reentry management message may be
omitted.
Bit #0: Omit AAI_SBC-REQ/RSP
management messages during reentry
processing
Bit #1: Omit PKM Authentication phase
except TEK phase during current reentry
processing
Bit #2: Seamless HO
Bit #3: TBD.
Ranging initiation
deadline
Service level prediction
Shall be included for each target
ABS when Mode=0b00
Indicates the level of service the AMS can
expect from this ABS. The following
encodings apply:
Shall be included for each target
ABS when Mode=0b00
0 = No service possible for this AMS
1 = Some service is available for one or
several service flows authorized for the
AMS
2 = For each authorized service flow, a
MAC connection can be established with
QoS specified by the
AuthorizedQoSParamSet.
3 = No service level prediction available.
Physical_Carrier_Index
Physical carrier index of the Target ABS
where AMS will perform network reentry
procedure.
Should be included for each target
ABS which is multi-carrier ABS
when Mode = 0b00
Carrier Preassignment
Indication
1: information of pre-assigned secondary
carriers by the target ABS is included in this
message;
Shall be included for an AMS with
multi-carrier capability when Mode
= 0b00
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IEEE C802.16m-09/1886
0: no pre-assigned secondary carrier
N_Preassigned_Carriers
Number of pre-assigned secondary carriers
at the target ABS. A value of 0 means no
secondary is pre-assigned.
Shall be included when
MCHO_Indication = 1
Pre-assigned secondary
carrier information
Carrier information of each pre-assigned
secondary carrier, which includes:
Shall be included when
N_Preassigned_Carriers > 0
LZone information

Carrier Status Bitmap: indicating
whether this pre-assigned carrier will
be activated immediately after HO
procedure is done;

Physical carrier index of pre-assigned
secondary carriers;

Logical carrier index, which is assigned
implicitly in the order of Carrier
information of each pre-assigned secondary carriers.
LZone information for the AMS to switch
from MZone to LZone.
Shall be included when Mode =
0b01.
----------------------------------------------------------- Text End --------------------------------------------------------------{Delete the following text from P802.16m/D1, starting at Section 15.2.7.2.9.2.3, page 128}
----------------------------------------------------------- Text Start -------------------------------------------------------------15.2.7.2.9.2.3 MAC management messages for MCHO
The support of multi-carrier handover will reuse the same messages as defined in 15.2.5.1, 15.2.5.2, 15.2.5.3
and 15.2.5.4. The parameters to be included into each MAC message to support multi-carrier handover are list
as following.
15.2.7.2.9.2.3.4 AAI_HO-IND
The AAI_HO-IND message may include the following parameters:
•Physical_Carrier_Index: Physical carrier index of the Target ABS where an AMS will perform network reentry
procedure.
15.2.7.2.9.2.3.5 AAI_HO-REQ
The AAI_HO-REQ message shall include the following parameters:
•Multi-Carrier_Support: If Multi-Carrier_Support is set to 0, the AMS only supports single-carrier handover
procedure defined in 15.2.6.3 and will disconnect all its active secondary carriers before handover; otherwise,
the AMS supports the multi-carrier handover procedure defined in section 15.2.9.2.9.2. No matter the AMS
which is capable of multi-carrier operation is in single-carrier mode or multi-carrier mode
For Multi-Carrier_Support = 1, the AAI_HO-REQ message may also include the following parameters:
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IEEE C802.16m-09/1886
•Carrier_Preassignment_Indication: indicates whether AMS needs pre-assignment of secondary carriers at the
Target ABS
15.2.7.2.9.2.3.6 AAI_HO-CMD
The AAI_HO-CMD message shall include the following parameters:
•Multi-Carrier_Indication: If Multi-Carrier_Indication is 0, the AMS shall disconnect all its active secondary
carriers and perform single-carrier handover procedure per 15.2.6.3; otherwise it performs multi-carrier
handover procedure per 15.2.9.2.9.2.
For Multi-Carrier Indication = 1, the AAI_HO-REQ message also includes the following parameters:
•N_Preassigned_Carriers: Number of pre-assigned secondary carriers. A value of 0 means no secondary is preassigned.
•Carrier_information of each pre-assigned secondary carrier if N_Preassigned_Carriers > 0. In this case, the
AAI_HO-CMD further include the following information:
•1-bit carrier status indicating whether this pre-assigned carrier will be activated immediately after HO
procedure is done.
•Logical carrier index is assigned implicitly in the order of Carrier_information of each pre-assigned secondary
carriers.
•Physical carrier index of pre-assigned secondary carriers
----------------------------------------------------------- Text End ---------------------------------------------------------------
10